In order to have healthy lifestyles, cases of people personally making and drinking vegetable juice or other types of juice in homes have been on the rise. In line with this trend, various types of juice extraction apparatuses, such as juicers, that can be conveniently used in homes have been developed.
In general, conventional juicers are operated in such a manner that fruit or vegetables are accommodated in a housing equipped with a juice extraction screw assembly and the fruit or vegetables are ground and pressed by rotating the juice extraction screw assembly via a drive motor, thereby extracting juice.
Although these conventional juicers are advantageous in that grinding can be performed in a short period of time because fruit flesh, etc. can be ground into small pieces by the juice extraction screw assembly driven at a high speed, they exhibit a limitation in usage when a user desires to have fruit flesh, together with juice, depending on the type of fruit
Recently, a method of extracting juice by squeezing fruit or vegetables while rotating a juice extraction screw assembly at a low speed has been used as a method of extracting juice. This method requires considerably high force in order to reduce the rotation speed of the juice extraction screw assembly and squeeze juice.
Korean Patent Application Publication No. 10-2007-0066720 discloses a food processing apparatus including a plurality of gear reduction gear trains disposed in a plurality of vertical stages, wherein each of the gear reduction gear trains includes a sun gear and a plurality of planetary gears.
Korean Patent Application Publication No. 10-2006-0117616 discloses a gear reducer that performs gear reduction via one or more combinations of planetary gears.
However, the above-described conventional technologies are problematic in that the number of planetary gears or the number of gear reduction gear trains should be considerably increased in order to achieve a high gear reduction ratio. In addition, when the number of planetary gears or the number of gear reduction gear trains is increased, another problem arises in that the internal space of a juicer should be increased accordingly.